I love the shift chime
#4
RX-7 Bad Ass
iTrader: (55)
I think my buzzer is dead, my CPU#2 has all kind of goofiness and I'll probably replace with a new one.
The FC's had the buzzer in the instrument cluster, which makes a lot more sense. Closer to your head and easier to hear. I could clearly hear the one in my VERY loud old FC (open wastegate).
Dale
The FC's had the buzzer in the instrument cluster, which makes a lot more sense. Closer to your head and easier to hear. I could clearly hear the one in my VERY loud old FC (open wastegate).
Dale
#7
So it's right at red line.
But if it doesn't work on non stock ECU, I wonder why that is. There is no dedicated shift chime warning from the engine ECU, and it can't be from the trans ECU because then it would only work on automatics. Maybe it gets a tach signal through the data link connector or cluster, and then processes the signal before the chime. Nowadays it would all be messages over a CAN bus.
Trending Topics
#8
RX-7 Bad Ass
iTrader: (55)
Interesting! There should be a way to make it work again. I never associated the lack of beep with the ECU.
Time to dig out the wiring diagram .
Dale
Time to dig out the wiring diagram .
Dale
#10
Senior Member
Hmm, is that activated by the main ECU or this ECU #2 that Dale mentioned? With an AEM EMS it would be easy to output +5V on a sensor line to have the buzzer go off whenever you want. I don't know if the PowerFC has the same kind of capability but I assume it does? I only have experience with AEM EMS on other cars.
#11
So it's listed under CPU #2 functions, that's where that image came from. The CPU is what would be called the body control module in a modern car. Instead of communicating through a digital connection (CAN message) it communicates with the rest of the vehicle by analog signals.
I spent a while digging through the service manuals, wiring diagrams, and service highlights. Here's how it works.
The warning chime comes from the CPU #2, based on a signal that comes from the cluster.
The CPU #2 receives a signal at pin 1L for a warning. That includes the warning chime for low coolant level as well. The cluster makes the determination for a warning chime based on different inputs, such as the low coolant sensor. For the overrev chime, it is getting a tach signal from pin 2B on the engine ECU, which is routed through the diagnostic connector under the hood.
I'm thinking aftermarket ECUs, including the Power FC, don't output a tach signal on pin 2B. This is based on looking at the documentation. I haven't gotten in there and confirmed but I'm 90+ % sure. The service manual specifically says to check pin 2B on the engine ECU if you are not getting the overrev alarm. And the pinout of the ECU gives a specification at 3000 rpm, indicating that it is a tach signal.
I spent a while digging through the service manuals, wiring diagrams, and service highlights. Here's how it works.
The warning chime comes from the CPU #2, based on a signal that comes from the cluster.
The CPU #2 receives a signal at pin 1L for a warning. That includes the warning chime for low coolant level as well. The cluster makes the determination for a warning chime based on different inputs, such as the low coolant sensor. For the overrev chime, it is getting a tach signal from pin 2B on the engine ECU, which is routed through the diagnostic connector under the hood.
I'm thinking aftermarket ECUs, including the Power FC, don't output a tach signal on pin 2B. This is based on looking at the documentation. I haven't gotten in there and confirmed but I'm 90+ % sure. The service manual specifically says to check pin 2B on the engine ECU if you are not getting the overrev alarm. And the pinout of the ECU gives a specification at 3000 rpm, indicating that it is a tach signal.
#13
RX-7 Bad Ass
iTrader: (55)
Nice! I'll have to experiment with that sometime.
Dale
Dale
#15
Rotary Enthusiast
iTrader: (9)
I got the shift chime with my PowerFC when getting up around 7500rpm autocrossing
Assuming it wasn't the PFC warning me about something else (ie running out of injector). AFAIK the PFC only has the flashing "exhaust overheat" light as a warning feature and the shift chime is built in to the car as arghx said
Assuming it wasn't the PFC warning me about something else (ie running out of injector). AFAIK the PFC only has the flashing "exhaust overheat" light as a warning feature and the shift chime is built in to the car as arghx said
#18
so it sounds like the PFC does have the tach output, although I've driven PFC cars that don't have a shift chime. They must have had something else going on--bad cluster or bad CPU #2. I would think that most any other aftermarket ECU would not have output to the cluster.